Destabilization of the lumbar spine results from sacrifice of the anterior longitudinal ligament and disc when removed for graft or cage placement. Similarly, transection of the interspinous ligaments during surgical approaches to the posterior spine may result in instability. Such instability may cause abnormal motion or implant migration resulting in a high incidence of pseudarthrosis.
In anterior interbody surgical procedures, the anterior longitudinal ligament is sacrificed, resulting in instability which can lead to hyperextension and interbody device migration.
Current anterior spinal interbody fusion procedures are performed either standalone, using a buttress plate or using anterolateral or posterior rigid fixation. Interbody motion devices are implanted without augmenting the device, since no device is available that can provide stability and containment yet allow for normal range of motion. This is a particularly challenging problem when dealing with the normal range of movement of the spine.
U.S. Pat. No. 5,681,310 “Yuan” discloses a holding mat for preventing a foreign object from jutting out of the vertebra. The mat is attached using a plurality of fastening elements and all components are capable of being assimilated into the tissues of a human body. However, the device is not specifically designed to facilitate regeneration of a mechanically appropriate repair tissue, but only to contain foreign objects within the vertebra.
U.S. Pat. No. 6,371,990, “Ferree”, discloses a flexible, biocompatible material that is attached to adjacent vertebral bodies for the purpose of fortifying the annulus fibrosis. The device is used in conjunction with a device for covering the inner wall of the annulus. Ferree discloses using treated pig intestine combined with the invention to promote tissue ingrowth. However, the device is not specifically designed to facilitate regeneration of a mechanically appropriate repair tissue.
U.S. Pat. No. 6,221,109, “Geistlich”, discloses a collagen membrane wrapped around the vertebrae and disc for protection of the spinal cord from implants jutting out of the disc space. The device is used in conjunction with a collagen membrane wrapped around the spinal cord. The device is not specifically designed to facilitate regeneration of a mechanically appropriate repair tissue and appears to be limited to the posterior aspect of the spine surrounding the spinal cord.
U.S. Pat. No. 6,093,205, “McLeod”, discloses a fabric element attached to adjacent vertebrae for the purpose of retaining a specific disc prosthesis described in the invention. The fabric may be made of a resorbable material and may have structure and/or properties to encourage tissue ingrowth. The fabric may be attached using sutures, staples, and bone screws. The device is not specifically designed to facilitate regeneration of a mechanically appropriate repair tissue and is disclosed as an integral part of the disc prosthesis described.
U.S. Pat. No. 5,372,821, “Badylak”, discloses a method for promoting autogenous regrowth of damaged or diseased ligaments by attaching small intestinal submucosa. No mention is made to spinal ligaments, attachment thereof to the spine, or as an augmentation to an intervertebral disc surgical therapy. Similarly, U.S. Pat. No. 5,922,028, “Plouhar”, discloses a tissue graft construct for repairing or replacing a cartilaginous structure located between two bones comprising small intestinal submucosa with 50 to 200 layers and thickness of 4-8 mm and sculpted to the proper shape. Although the patent refers to reconstructing the intervertebral disc, no mention is made to regenerating the spinal ligaments, to achieving a mechanically appropriate repair tissue, or as an adjunct to an intervertebral disc surgical therapy.
Thus there is a need in the art for bioabsorbable, anterior longitudinal ligament and interspinous ligament replacement implants that serve to restore stability following surgical removal of the native ligaments, contain intervertebral body devices or grafts, and encourage regeneration of a functional repair tissue for long-term stability such as described in this invention.